The popularity of battery-operated portable electronics with wireless connectivity has driven the design of radio frequency (RF) analog circuitry to consume less power while maintaining or increasing performance. The fabrication of these complex circuits using complementary metal oxide semiconductor (CMOS) fabrication processes increases variability over voltage, temperature, age and the like, resulting in lower yields. The requirement for low power and high yield is difficult to achieve using traditional static circuit design techniques. Thus, there is a need for adaptive or reconfigurable wireless systems that use underlying tunable RF, analog or mixed-signal elements. By using a tunable element such as a tuning circuit, a wireless system is more capable of improving power consumption and performance considering variables such as environment, process or performance requirements. Such adaptability is enabled using tuning elements in circuits to allow a trade-offs between various criteria such as power consumption and performance. However, a tuning element used in a traditional RF circuit design typically impacts multiple performance criteria, making it more difficult to adjust a tuning element for a particular criteria. Further, traditional circuit designs may lack sufficient tuning elements to achieve independent or orthogonal control of any particular criteria.
Furthermore, traditional wireless circuits and systems are typically overdesigned to allow operation in various environments, which impact wireless channel conditions by adding delay spread, fading, co-channel and adjacent channel interferers/blockers and the like. RF systems are typically designed to adapt to such environments by trading-off the performance of the RF receiver's front-end circuits to reduce power consumption during stronger channel conditions. For example, when the received signal strength is moderate and there is no co-channel or adjacent channel interference/blockers, the linearity of the low-noise amplifier (LNA) may result in the LNA consuming more power than needed.
In addition, increased semiconductor process variations may lead to loss of yield as components fail one or more performance criteria. Further, RF circuits and systems typically exhibit lower yields than digital circuits and systems due to the interdependence and complex nature of multiple performance criteria and the inability to adequately adjust for such performance criteria. Accordingly, there is a need for techniques to independently or orthogonally tune various performance criteria of amplifiers. Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and claims, taken in conjunction with the accompanying figures and the foregoing technical field and background.